Sup guys. Most likely I already know the answer here, but wanted some hivemind input before I tear into things. I've got a whining/whirring noise from the front cover. 500 miles so far on this fresh rebuilt motor.

Vids:


With all accessories off, it actually sounds louder to me:



I first wrote this off as a noisy alternator, PS, or accessory but removing the belts was clear we've got something greater here. Heart sank, went through the stages of rotary denial, etc. Now I'm pretty convinced that front cover needs to come off for inspection.

Things I believe I've ruled out:

Alt/water pump/power steering. There's no air pump on this thing.
Tested for vac leaks around the LIM and UIM junctions. Nothing found.
Trigger wheel isn't rubbing on anything.
Sound doesn't change with clutch in/out, makes me think it's not something back there.
Using the long screwdriver stethoscope method, whirring is coming from front cover area. The camera mic also really picks it up when you put it in front of the pulley.
Turbos are silent.

There were no chunks in the oil or filter but plenty of sheen (suspended micro particles) in the first two oil changes (one at 50mi and one at 250mi so far). I wrote that off to break-in, but now I'm definitely thinking twice. I got the rebuilt motor in a deal with the car, it's from a reputable engine builder and came straight from their workshop. As such I didn't ever pull the front 19mm crank bolt (I did pull the 4 10mm bolts to install banzai pulley). In hindsight I wish I would have checked endplay on the bench and paid closer attention to noises before putting any miles on it.

I of course suspect funkiness in the torrington or oil pump area judging by these symptoms, though I'm a rotary noob and highly value input of those who have been doing this for so long. I have stopped driving it immediately once I realized the sound is internal. 500 miles total so hopefully she's salvageable.

Appreciate input!

 

Oh man...Sucks to see.... but yeah, the front cover needs to come off.

Make sure you're careful removing the front hub bolt.
There are write-ups on removing it correctly, so the thrust bearing doesn't drop.

G/L

Steve

 

Thanks Steve! I'm already planning on exactly that, though you confirming that makes me feel better somehow. I stopped running it as soon as I realized it was from the motor and not an accessory, so hopefully I didn't damage anything else.

Here's a question, though. Pull the motor or do this in the car? I looked at a few guides and it definitely looks like it could be done in place, though pulling the motor would be easier to re-stack the front stack and set endplay, etc. Also I'll want to re-seal the pan while I'm in there.

 

I'd pull the motor for that job. It's just so much easier to re-stack, accurately check end play & reseal the pan when it's on an engine stand.

 

That is also the direction I'm leaning. Out she goes!

Thanks guys.

 

I've pulled the front cover in the car and out. IMPO its not really harder either way, but if you want to check endshaft play.... I wouldn't attempt that while the engine is in the car.

Hey, its not like this is some kind of V12 where you need a big ole hoist to pull the engine.

 

I have always wondered why I have not heard about more trouble with the chain driven oil pump set up.

Is it that robust?

Local shops here do not seem to have many quams about reusing old oil pump set-ups in rebuilds.

There is also the mechanism driving the OMP to consider, if it is still there.

 

I was wondering if it was OMP related as well. Either way, I agree with pulling the motor out and pulling the front cover off is the correct approach. Good luck.

 

Seems like a fairly 'large' noise to be coming from the little OMP to me. It'd have to be really busted to be making that much racket so audible over everything else.

 

I'll unplug the OMP just to rule it out. And I've heard idle valves make a racket before so I'll unplug that too just to be sure. I'm also gonna check on the lift to ensure it's not coming from the back somehow, like the throw out or pilot bearing. Assuming it's none of that, out the motor comes. I feel pretty confident it's coming from the front stack behind that cover, in hindsight I really should have checked endplay on this freshly rebuilt motor and not have assumed anything, but honestly I'm a rotary noob and tend to learn stuff the hard way.

 

Unless I am getting my generations confused, I believe there is a driveshaft built into the front cover that turns the OMP pump. I don't see it in the FD FSMs however. (I see the electric stepping motor.)

One would think an engine rebuilder would be aware of the needle bearing drop risk, but perhaps someone else has had ocassion to loosen up the pulley bolt?

Have you sent the video clips to the builder?

 

The OMP on the FD (and S5s too I believe) is electrically controlled via the ECU. There isn't a mechanical connection at all.

 

What i sthat tongue for?

 

What does that gear wheel do?

 

That is evidence that I didnt pay enough attention when removing mine. And clearly electronically-controlled does not preclude being mechanically-driven. I stand corrected.

 

Very useful info. Sounds like if I want to rule this out I'd be better off blocking it off with a blockoff plate. But even then there's a driveshaft behind that cover that could be messed up somehow as well.

 

You can check the end play while in the car to confirm what you think. With the belts off and the clutch out, you should be able to feel the stack height space by grabbing the main hub with your hands and pulling/pushing in/out. Sticking a dial indicator on the intercooler support and measuring to the front bolt would be best, but you can measure the space between the trigger wheel and the cas sensor in a pinch.


~ GW

 

Fourth diagram page C-77 might be important. First diagram immediately below as well.

 

Seems you might get an indication of needle bearing drop by taking the measurement in diagram four above.

The gap between yourCAS and the trigger wheel might also be a clue.

 

Thanks for the FSM pics Redbul! You guys have been very helpful. I'm feeling pretty confident this is the needle bearing drop issue, but I'll be digging into it tomorrow since I'm off work and likely just pulling the motor then.

I will say I tried seeing if there's any endplay with the motor in the car and I certainly couldn't detect any with my dial gauge. That was prying the pulley towards the front of the car against the front case, and using the clutch (pull type) which I believe should pull the stack back. Neither direction had any detectable play.

 

Needle bearing issues lead to a metric ton of endshaft play. I got first hand experience there.

 

I've heard they start with no endplay and eventually progress into all of the endplay once the pinched bearing is ground down. I'm hoping I'm still in the early stages on this one.

 

Is CAS/Ttrigger Wheel gap normal?

 

There is plenty of gap there (I made sure it wasn't rubbing), though I'm not sure what normal is. Would you expect more or less gap with a pinched needle bearing?

 

You have your answer.

With the clutch pushed in it will pull the e shaft back. That’s your base measurement. With the clutch out, you should be able to pull it forward 1-3 thou. If you have zero, then it’s pretty apparent.

The trigger wheel trick is used as a quick check. You would put some feeler gauges in there to see how much end play you have doing the same thing with the clutch pedal. The dial indicator is still the best.

~ GW